Proximity services (ProSe) refer to schemes for supporting communication between devices located physically close to each other. Specifically, ProSe is aimed to discover an application operating between devices which are in proximity and, ultimately, to support exchange of application-related data. For example, ProSe may be applied to applications such as social network services (SNS), commerce, and games.
ProSe may be also called device-to-device (D2D) communication. That is, ProSe refers to a communication scheme for establishing a direct link among a plurality of devices (e.g., user equipments (UEs)) and thus directly exchanging user data (e.g., voice, multimedia data, etc.) between the devices without going via a network. ProSe communication may include UE-to-UE communication, Peer-to-Peer communication, etc. Further, ProSe communication may be applied to Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), etc. Accordingly, ProSe is considered as one solution for reducing the burden of a base station due to rapidly increasing data traffic. Besides, by adopting ProSe, effects such as reduction in procedures of a base station, reduction in power consumption of devices which participate in ProSe, increase in data transmission speed, increase in network capacity, load distribution, cell coverage expansion, etc. can be expected.
In addition, IP (Internet Protocol) Multimedia Subsystem (IMS) refers to an architectural framework for providing IP multimedia service in a variety of wired/wireless communication networks. The IMS uses a protocol applicable to various networks, e.g. Session Initiation Protocol (SIP). The SIP is a signaling protocol for controlling a multimedia service session using an IP, and can be used to set up, modify and terminate a unicast or multicast session. That is, the IMS helps users to easily access multimedia and voice data using a variety of wired/wireless devices.
A session(s) including one or more media flows (or media streams) may be configured using the IMS. The IMS session may be expressed in such a manner that a local side and a remote side are logically connected to each other via IMS network nodes. Here, a peered user equipment (UE) or server of a local-side UE may be called a remote end or a remote party. That is, a remote end is an entity for exchanging media flows with a local-side UE via an IMS network.
While adoption of ProSe is demanded as described above, a mechanism for supporting and controlling ProSe is not specifically prepared.